Purchased and installed new Roku Premiere. We have experienced a popping sound and pixelation on home screen. We have been able to access some of the apps, but the sound sometimes goes out after only a few minutes of viewing and the video appears "snowy". We have restarted and reset several times, but that didn't correct problem. We also tried plugging the Roku into a different HDMI port. Didn't help. Tried using an HDMI cable from our older Roku device and, when that didn't work, we purchased a new cable. Didn't help. Any suggestions?